Callosities upon the heel, sometimes so bad as to be called corns, are often troublesome, and mostly so to those persons whose feet are bony and spare of flesh. In these, if they are not broken down, the heel bone, at its upper part, projects backward distinctly. If the boot worn slips at the heel, there is no flesh over the bone to ease the pressure and friction of the leather, and the skin must thicken for its own protection. After a while it becomes so thick, callous, and hard, that every pressure upon it hurts the bone, as much as before it was formed. It has become similar to a hard corn, and must be removed. This can often be done without any softening, by carefully cutting, scraping, or lifting up gradually with the knife. It will probably grow again, and need relifting occasionally as long as the irritation continues. It is due to flat feet to say that they usually escape these annoyances, as well as sores of the instep. Slipping of the boot at the heel, is almost always the fault of the boot-maker. It may come from bad cutting, from bad fitting of the upper, from bad lasting, and from badly shaped lasts upon which the boots are made. When the cutting is wrong—which affects _men’s_ boots mainly—it is the leg through the ankle that is too large, or there is some defect that will not allow the upper to _last_ properly. Sometimes it is fitted badly, so as to produce the same result. More often than either of these it is the workman, who neglects to draw it over the last in the right way; sometimes from want of knowledge, and sometimes from carelessness or indifference. The error consists in not drawing it over the toe sufficiently tight to make it fit closely at the heel. A bad fit upon the foot is another cause, in addition to those mentioned; and it is also true that the heels of well-arched feet are more liable to slip than those whose arches are more or less flattened down. Still another and very decided influence in producing callosities on the heel, is a counter that is hard and stiff at its upper portion. Counters of this kind are very common, and ought to be as commonly avoided. The stiffness of a counter _should be at the bottom of it, where there can hardly be too much, while the upper half, or more, should taper to a thin edge, that is soft and flexible_. Then, while firm at the proper place, it bends and fits snugly to the heel, preventing its slipping; when, if it stands up straight and stiff throughout, the foot will slip almost invariably.